Compact living, it’s not.

You could fit more than 30 microapartments inside the largest penthouse on the market in Greater Boston. While its 7,700-square-foot living space is unlikely to trigger claustrophobia among future occupants, outdoorsy types can step out onto a 12,000-square-foot roof terrace, for a combined half-acre of rooftop living with 360-degree views of the Boston skyline, Mystic River and the popular Wegmans supermarket at the newly redeveloped Meadow Glen Mall.

Alex Wong, the listing agent for Keller Williams Realty, describes it as a “one-in-a-million opportunity” to buy a unique property that’s never been on the market since it was completed 30 years ago.

Occupying the entire top floor of the 12-story tower at 3920 Mystic Valley Parkway in Medford, the living spaces are so expansive that some potential buyers have inquired about converting part of the unit into commercial office space, Wong said. (Condo rules forbid such an arrangement.)

Listed for $4.7 million, it’s a bargain compared with downtown Boston listings such as a 5,700-square-foot penthouse at The Archer Residences on Beacon Hill, currently listed for $18 million (that property’s roof terrace is a mere 2,326 square feet).

The original developer saved the entire top floor for a personal residence, Wong said, and never rented it out. Most of the decor – think lots of pink marble – dates back to its completion in 1988. But the owner recently invested $120,000 on new artificial turf for the roof terrace. The unit also comes with a private elevator, six parking spaces and solarium.

Property records identify the owner as Marotta Family Holdings of Boca Raton, Florida, a corporation which lists former Medford mayor and state representative Angelo Marotta as its manager.

“The lifestyle could be as good as other high-rise buildings,” Wong said. “If a future owner wanted to do some work, I would say it would only be cosmetic because the quality of the craftsmanship is very good.”